EFFECTS OF DANAZOL ON ENDOMETRIAL DNA-SYNTHESIS IN RATS

The suppressive effects of Danazol, an isoxazol derivative of the synt hetic steroid 17 alpha-ethinyltestosterone, on endometrial DNA synthes is were investigated in rats by immunohistochemistry with bromodeoxyur idine (BrdU) and DNA-synthesizing enzyme assays. Rats treated with Dan azol for 14 days at 17-19 weeks of age showed a decrease of plasma gon adotropins associated with ovarian hypofunction, persistent diestrus, and a smaller number of corpora lutea in ovary, resulting in no BrdU-i mmunoreactive (S-phase) cells in endometrial epithelium and lower acti vity of thymidine kinase in the uterus compared with control.